Help Setting up an electronic workbench

JMB

Member
2004-04-01 8:47 pm
Texas
Hi All,

I have been mostly doing loudspeaker design but have recently found my interest piqued in electronic troubleshooting. I have no electronic background but I have some basic skills.

I mostly want to troubleshoot amplifiers and audio electronics.

I would like to get some input as to what electronic equipment would be most useful and for what to start out troubleshooting. Obviously, I have DMM's. I was given a Digital Counter and a 20 MHz Oscilloscope by my Brother in law.

Thanks for your input.

Jay
 
Well, it sounds like you need something to fix...

I suppose you already have tools. Desoldering wick and a solder sucker are very helpful. A signal generator is very useful too. Having two sets of probes for your scope is handy.

If you have no background or experience with electronics, building something from the ground up is very educational. Plus, it rarely works the first time, so you get your troubleshooting too.;)

Here is a signal generator you can build:

http://sound.westhost.com/project86.htm

Here is a source for cheap electronic tools:

http://www.circuitspecialists.com/

Have fun!
 

JMB

Member
2004-04-01 8:47 pm
Texas
Thanks for your reply. I have an old Yamaha R-700 that started out with power and no audio output. As I was tracing continuity, I slipped, a spark occured, and now, no power.

I realize that it is probably not going to be cost effective to repair, but felt that it might be fun to use this piece of equipment as a troubleshooting teaching tool.

I would prefer not to build at this point (time limitations) though it would be reasonable in the future. For now, I would prefer to purchase the test equipment (unless the build would not take long).

I assume that either a function generator or signal generator would be used to assess AC functions in cohjunction with the oscilloscope?

I assume that I would not need to go to particularly high frequencies with the generator for audio. It seems that most go to about 2Mhz, is this reasonable?

Should I get a generator that has BNC outputs to hook directly into the oscilloscope; and if so, exactly what function is this playing in the troubleshooting (I'm sorry that my questions are so basic)? I plan to teach myself how to properly use the oscilloscope.

Is it necessary to have a bench top power supply, such as either an old converted computer power pack or a variac?

Is the continuity tester on my DMM adequate or do I need a signal tracer?

Thanks, again, Jay
 
"...I slipped, a spark occured..."


I've done that too.

The function generator doesn't need to go above 20kHz (imo), and it doesn't have to have BNC connectors. You can get any adapter you want. Its just nice to have to make sure your device is working properly - its easier and less risky than hooking up a cd player or computer to a possibly unhappy piece of gear - and you can watch for distortion/frequency anomalies on the scope.

The Yamaha is a good starting place - but its probably pretty complex. If you don't have the schematic (and service manual) available, you don't have a chance (imo, again).

I don't have a dedicated benchtop PSU, although a variac would be very useful. Personally, I need a way to watch the current drawn (in case of shorts). I think people stay away from computer PSUs because they are switching supplies, and have lots of very high frequency content, and not a lot of amperage at some voltages.

A good starting project would be one that people on this board have experience with. That way, when you have very specific questions, its likely someone here will know the answer. There are a lot of people here modifying commercial amps, and that would probably be an easy and less frustrating entry into fixing electronics.

This website is an excellent resource, but books are still very useful. "The Art of Electronics" by horowitz and hill is a classic.